Preheat your oven to 180ºC (160ºC fan-assisted) and line a cupcake tray with 12 paper cases.

Using a stand mixer or handheld whisk, cream together the unsalted butter and light brown sugar until the mixture becomes pale and fluffy.

Gradually add the eggs, one at a time, ensuring each is fully incorporated before adding the next. Mix in the vanilla extract for an added layer of flavor.

Sift together the self-raising flour and cocoa powder, then gently fold these dry ingredients into the wet mixture until smooth and evenly combined.

Evenly divide the cupcake batter between the prepared cases, filling each approximately two-thirds full.

Bake for 20–22 minutes, or until the cupcakes are springy to the touch and a skewer inserted into the center comes out clean. Allow the cupcakes to cool completely on a wire rack before decorating.

Soften the unsalted butter by beating it alone for 2–3 minutes, creating a smooth and creamy base.

Gradually add the icing sugar, mixing thoroughly after each addition. Pour in the vanilla extract and continue to whip until the buttercream is light, fluffy, and fully combined.

Add the green food coloring a little at a time, blending thoroughly to achieve a vibrant festive shade. Adjust the intensity by adding more food coloring as needed.

Attach a 2D closed star piping nozzle to a piping bag filled with the green buttercream. Pipe tall, swirled layers of buttercream onto each cupcake, resembling the shape of a Christmas tree. Leave small sections of the sponge visible to mimic a snowy effect.

Gently press colorful sprinkles into the buttercream to imitate decorative ornaments.

Place a chocolate star on the peak of each buttercream tree.

For the finishing touch, lightly dust the cupcakes with icing sugar to evoke freshly fallen snow.